We understand your concern for your fiancé's health and we will pray for his healing and recovery. First, remember Jesus is the way to the Father. We only have access to the Father in his name. It is wonderful you ended your prayer correctly. The power in the name of Jesus is explained in Acts 4:10-12 WEB:
...be it known to you all, and to all the people of Israel, that in the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead, in him does this man stand here before you whole. He is 'the stone which was regarded as worthless by you, the builders, which has become the head of the corner.' There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved.
We are also reminded to pray in faith. Jesus said in Mark 11:24 Therefore I tell you, all things whatever you pray and ask for, believe that you have received them, and you shall have them.
Let us pray together.
Dear Heavenly Father,
We come before you in the name of Jesus, lifting up our ###'s fiancé who is ill. We pray for his healing and recovery, and we ask that you strengthen his immune system and make him whole again. We rebuke the spirit of infirmity and command it to leave his body in the name of Jesus.
Father, we know that you are the same yesterday, today, and forever, and that you can perform miracles even today. Just as you healed the blind and raised Lazarus from the dead, we ask that you perform a miracle in our ###'s fiancé's life and heal him completely. We ask that your will be done for your glory and the glory of your Son Jesus Christ.
Father, we also pray for our ###, that you would comfort her and give her peace during this time. We ask that you would give her the strength to endure this trial and that you would draw her closer to you as a result.
We ask all of this in the name of Jesus, our Lord and Savior. Amen.
Lastly, we want to encourage you to continue to trust in God and to pray without ceasing. Remember that God is in control and that he loves you and your fiancé more than you can imagine. Do not lose hope. Continue to stand on God's promises and to believe that he is able to do far more abundantly than all that we ask or think, according to the power that works in us. Ephesians 3:20 WEB.
We are also reminded of Isaiah 53:5 WEB But he was pierced for our transgressions. He was crushed for our iniquities. The punishment that brought our peace was on him; and by his wounds we are healed.
Therefore, continue to pray and trust in God, and remember that he is faithful to his promises.